package com.int_tech.utils;

/**
 * Created by liubch on 2018/2/7.
 */
public class latlngLength {

    public static void main(String args[]) {
        System.out.println("Hello World!");


        double lng1 = 39.450440;
        double lat1 = 116.264810;
        double lng2 = 39.450727;
        double lat2 = 116.265823;


        double sss = GetDistance(lng1,lat1,lng2,lat2);

        System.out.print(sss);


    }


    //地球半径
    private static final double EARTH_RADIUS = 6378.137;
    /**
     * 根据经纬度查询距离
     * @param lng1 经度
     * @param lat1 纬度
     * @param lng2 经度
     * @param lat2 纬度
     * @return
     */
    private static double GetDistance(double lng1,double lat1, double lng2,  double lat2)
    {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lng1) - rad(lng2);

        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) +
                Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
        s = s * EARTH_RADIUS*1000;
//     s = Math.round(s * 10000) / 10000;
        return s;
    }
    private static double rad(double d)
    {
        return d * Math.PI / 180.0;
    }
}
